An acromio-clavicular strain is an injury to the shoulder, where the collar bone (clavicle) meets the scapular (shoulder bone).
Most people get an acromio-clavicular strain when they fall onto their shoulder, or else land and take the weight on their outstretched arm or elbow. The pain is usually felt in the bony bit on the top of the shoulder.
An acromio-clavicular strain can range in severity from a small pain to a complete rupture of the joint, with the collar bone protruding from the neck.
Typical symptoms of this injury include:
- Pain at the end of the collar bone
- Pain when you move the arm overhead
- A hard lump where the collar bone sticks up
If you suspect this injury, the first thing to do is RICE - Rest, Ice, Compression, Elevation - then get it checked out by a doctor or sports injury specialist.
They will make a diagnosis based on the mechanism of injury, your symptoms, an examination, and probably an x-ray.
Depending on the severity of the injury, they may initially immobilize it by taping the collar bone in place - this strapping will usually be needed for 2 to 3 weeks, after which you will need mobility exercises to loosen and strengthen the joint.
If the diagnosis is a total rupture, surgery will be needed to affect a complete recovery.